The present invention relates to a formulation of a pre-selected fragrance formulation and a fat and a solid surface active agent for use as a carrier for the pre-selected fragrance formulation for the purpose of imparting a fragrance to a laundry detergent composition, a fabric softener composition or a drier-added fabric softener article containing the fragrance/fat/surface active agent formulation used to increase substantivity of fragrances on fabrics. In another aspect, the present invention relates to a method of formulating a pre-selected fragrance formulation and a fat and surface active agent carrier for the pre-selected fragrance formulation.
The method of the present invention enables the production of fragrance-containing solid particles of improved substantivity for use in a variety of laundry detergents, fabric softener compositions and drier-added fabric softener articles.
It has been the practice in the past to impart fragrance to standard powdered laundry detergents by simply spraying the fragrance or aroma chemical onto the detergent base formulation. In such prior art developments, it is typical that the detergent contains at least 0.5% by weight of the fragrance formulation. In the course of the washing process wherein clothes are washed with the standard powdered laundry detergent, a very small fraction of the fragrance that is contained in the detergent is actually transferred to the clothes. Tests have shown that the amount of fragrance that is left as a residue on the clothes can be as low as 1% of the original small amount of fragrance that is contained in the detergent formulation itself. Hence, it will be seen that 1% of as little as 0.5% by weight fragrance is a very small amount of fragrance indeed.
One approach to solve this problem that has been used in the prior art is to employ a carrier to bring the fragrance to the clothes. The carrier is formulated to contain fragrance and to attach itself to the clothes during the washing cycle through particle entrainment or chemical change.
Another technique is that disclosed in U.S. Pat. No. 5,506,201 issued on Apr. 9, 1996 (McDermott, et al) wherein a method is disclosed for producing a fragrance containing solid particle for incorporation into laundry detergents by selecting a fat component such as a fatty acid glyceride, heating the fat component to an elevated temperature sufficient to form a molten melt thereof, selecting a solid surface active agent from the group consisting of SPAN.RTM. surfactants with an HLB of 4.3 to 8.6, heating the surface active agent to form a molten melt thereof and then combining the melts with an aroma chemical to form a mixture. The resulting mixture is rapidly cooled to form a solid material, and the solid material is formed into particles and the particles are added to detergent formulations. The SPAN.RTM. surfactants of U.S. Pat. No. 5,506,201 are mixtures of materials having the structures: ##STR1## wherein R is C.sub.11 -C.sub.17 alkyl or alkenyl. However, U.S. Pat. No. 5,506,201 does not recognize that in order to create intense long lasting fragrances which are substantive on cloth treated with detergents and/or fabric softeners and/or drier-added fabric softener articles, it is necessary to "pre-engineer" the fragrance in conjunction with the particular fragrance components, as well as the weight percentages of each component in the formulation and, in combination, formulate the fragrance-containing particle using a surfactant having an HLB of between 1 and 3 and, initially, drum chilling the fat/fragrance/surfactant combined molten mixture. Furthermore, the procedures of other prior art and formulations of other prior art have not been altogether successful because of the low substantivity of the fragrances. In the detergent industry, the term "substantivity" refers to the deposition of the fragrance on the clothes and the retention and perception of the fragrance on the laundered clothing and on the clothing treated with fabric softeners or drier-added fabric softener articles.